Field
The present invention relates to a vehicle.
Related Art
A fuel cell is mounted, along with a motor, on a vehicle to generate electric power with supply of a fuel gas and supply the generated electric power to the motor linked with an axle of the vehicle. The motor is driven with the electric power generated by the fuel cell, while regenerating electric power under regenerative control to brake the axle. The vehicle is decelerated with the braking force generated by the regenerative control of the motor during a run according to the requirement. Braking by regenerative control is applied mainly in the following two situations:
1) when the driver steps on a brake pedal for the purpose of braking the vehicle;
In this case, the intensity of regenerative braking is controlled to be proportional to the driver's depression amount of the brake pedal.
2) when the driver changes a shift lever to braking position provided in a shift device.
In this case, like engine braking in a conventional engine vehicle, a specific braking force by regenerative control is applied to the axle (driveshaft) irrespective of the driver's operation of the brake pedal. In this state, when the driver steps on the brake pedal, in addition to this braking force applied to the axle, a braking force corresponding to the driver's depression amount of the brake pedal is applied to the axle. Accordingly, this enables the driver to brake the vehicle with the higher deceleration force than the deceleration force during an ordinary run. The braking force corresponding to the driver's depression amount of the brake pedal is increased with an increase in initial regeneration level. In the case where the braking force only by regenerative braking is insufficient, a hydraulic brake or the like may be used to generate a higher deceleration force and decelerate the vehicle with the higher deceleration force. Such deceleration control technique is described in, for example, JP 2007-123169A.
This proposed deceleration control technique controls the braking force of the vehicle by adding a specific braking force to the ordinary braking force, when the driver changes the shift lever to the braking position. This deceleration control technique, however, requires the driver to return the shift lever to the drive position, in order to change the drive mode from an additional deceleration drive mode with the additional braking force to an ordinary deceleration drive mode that decelerates the vehicle with the ordinary braking force. Unlike the conventional engine vehicle, in a vehicle using a motor, such as a fuel cell vehicle, the gear ratio is not changed by the driver's operation of the shift lever. Changing the shift lever to the braking position accordingly does not change the magnitude of drive torque corresponding to the depression amount of the accelerator. Providing the braking position in a shift device and requiring the driver to operate the shift device may thus provide a feeling of strangeness. There is accordingly a need to relieve the driver's load to change the drive mode between an additional deceleration drive mode with additional braking force and an ordinary deceleration drive mode that decelerates the vehicle with only the ordinary braking force and without additional braking force.